In recent years, demand for cutting with high efficiency has been increased. Accompanying with this increase, a cutting tool having a longer tool life than that of the conventional ones has been required. Therefore, as characteristics required for the tool materials, it is more important to improve wear resistance and fracture resistance relating to lifetime of a cutting tool. Thus, as a coated cutting tool improved in these characteristics, a coated cutting tool which comprises a substrate such as a cemented carbide, cermet, cBN, etc., and one layer or two layers or more of a coating layer(s) such as a TiN layer, a TiAlN layer, etc., formed on the surface thereof has widely been used.
Various techniques for improving characteristics of the coating layer have been proposed for the purpose of further improvement in the above-mentioned wear resistance and fracture resistance. For example, in Patent document 1, a laminated coating member containing a predetermined crystal-oriented hard film has been proposed. The laminated coating member has a substrate, and a first coating layer and a second coating layer laminated thereon. These both of the coating layers are constituted by one kind of a single layer or two or more kinds of a plural layers of a nitride, a carbonitride, a nitroxide, a carboxide and a carbonitroxide of Ti and Al. The first coating layer has the maximum peak intensity at a (200) crystal face, and the second coating layer has the maximum peak intensity at a (111) crystal face.
In Patent document 2, a cutting tool insert comprising a cemented carbide body and a predetermined coating film has been proposed. The coating film is a single layer of (Ti1-XAlX)N (x is an atomic ratio, and is 0.25 to 0.50). In addition, the coating film is oriented to a (200) face with regard to the orientation.
As in the above-mentioned Patent documents 1 and 2, in the compound layer of Ti and Al, it has been known that the characteristics of the coating layer are controlled by controlling a diffraction intensity in the X-ray diffraction. In particular, it has been known that orientation is controlled to the (111) face, peeling resistance and oxidation resistance of the cutting tool are improved. In addition, it has been known that orientation is controlled to the (200) face, wear resistance of the cutting tool is improved.